Minor, remove unneeded codegen test

This test is already present in compiler/testData/cli/jvm/

compiler/testData/codegen/box/fullJdk/classpath.kt

@@ -1,18 +0,0 @@
-// TARGET_BACKEND: JVM
-
-// FULL_JDK
-
-import sun.nio.cs.ext.Big5
-import sun.net.spi.nameservice.dns.DNSNameService
-import javax.crypto.Cipher
-import com.sun.crypto.provider.SunJCE
-import sun.nio.ByteBuffered
-
-fun box(): String {
-    val a = Big5() // charsets.jar
-    val c = DNSNameService() // dnsns.ajr
-    val e : Cipher? = null // jce.jar
-    val f : SunJCE? = null // sunjce_provider.jar
-    val j : ByteBuffered? = null // rt.jar
-    return "OK"
-}